Chapter 9, Problem 15E

Program Plan Intro

Class “Octagon”

Program plan:

• Create an interface “Shape”,
  • Declare the methods “getArea()”, and “getPerimeter()”.
• Create a class “Octagon”,
  • Declare the variable.
  • Define the constructor to assign the initial value.
  • Define the method “getArea ()” to return the area calculated using the formula.
  • Define the method “getPerimeter ()” to return the perimeter calculated using the formula.
  • Define the method “main()”,
    • Construct “Octagon” object.
    • Print the value returned from the method “getArea()”.
    • Print the value returned from the method “getPerimeter()”.